How do you test for peak tax filing performance?

One of the problems that the IRS’s Modernized e-File team faced in performance testing was the ability to create a sufficient test load on the system to ensure it would perform under peak tax season use.

MeF Chief Engineer Terry Galloway said the goal was to create an environment that could drive the system at 200 tax returns per second.

"One of the things we learned from industry is that they weren't pushing those types of numbers of transactions, or the size of the load we were pushing," Galloway said. "No one could give us an example of a system handling those sorts of numbers."

And it wasn't enough to just produce that sort of load in short bursts, said MeF Release Infrastructure Manager Debbie Cook. She added that the testing environment had to be able to sustain that for long periods of time.

"You still cannot exercise the system fully until you can sustain that load," she said. So IRS had to build its own system internally with help from vendors.

Galloway said it's often a challenge to explain to new executives who come into the IRS from the private sector just how big the agency’s data processing load is.

"The argument they always make is that we're just like a financial institution," he said. "And my response to them is: Name a financial institution where every single taxpayer in the United States and every single company that sends funds through the U.S. is required to file documents in a specific time window. I don't know a bank that has every taxpayer going to them, one single bank that does that. So you can't compare those sorts of financial numbers to our requirements in a small window of time."